Review

Authors: Lauren M Stanoszek, Grace Y Wang, Paul W Harms...

CONTEXT

- Basal cell carcinoma (BCC) is the most common human malignant neoplasm and is a frequently encountered diagnosis in dermatopathology. Although BCC may be locally destructive, it rarely metastasizes. Many diagnostic entities display morphologic and immunophenotypic overlap with BCC, including nonneoplastic processes, such as follicular induction over dermatofibroma; benign follicular tumors, such as trichoblastoma, trichoepithelioma, or basaloid follicular hamartoma; and malignant tumors, such as sebaceous carcinoma or Merkel cell carcinoma. Thus, misdiagnosis has significant potential to result in overtreatment or undertreatment.

OBJECTIVE

- To review key features distinguishing BCC from histologic mimics, including current evidence regarding immunohistochemical markers useful for that distinction.

DATA SOURCES

- Review of pertinent literature on BCC immunohistochemistry and differential diagnosis.

CONCLUSIONS

- In most cases, BCC can be reliably diagnosed by histopathologic features. Immunohistochemistry may provide useful ancillary data in certain cases. Awareness of potential mimics is critical to avoid misdiagnosis and resulting inappropriate management.

Topics: Adenocarcinoma, Sebaceous; Biomarkers, Tumor; Carcinoma, Basal Cell; Diagnosis, Differential; Hamartoma; Histiocytoma, Benign Fibrous; Humans; Immunohistochemistry; Immunophenotyping; Skin; Skin Neoplasms

PubMed: 29072946
DOI: 10.5858/arpa.2017-0222-RA

Authors: Leonid Skorin, Scott A Bauer

PubMed: 32761197
DOI: 10.7556/jaoa.2020.103

Review

Authors: Bhavuray Teli, P B Thrishuli, R Santhosh...

Adnexal tumors like giant solitary trichoepitheliomas are uncommon to most of us to permit a ready familiarity with them. Information regarding the genesis, clinical profile, behavior, and management options for this tumor is limited. There are 18 cases reported in the world literature till date. This review attempts to provide insight to this rare tumor. Our search included indexed literature from Pubmed, Directory of Open Access Journals, Health Inter Network Access to Research Initiative and Google databases in addition to standard dermatology texts. Giant solitary trichoepithelioma is a rare trichogenic tumor with potential for local recurrence. It has predilection for the older age, but may present at any age including at birth. It has close resemblance to basal cell carcinoma and other skin adnexal tumors - clinically, cytologically, and histologically. CD10, CD 34, PHLDA1 but not p75NTR are useful adjunct markers. Surgical excision is the standard treatment. Recurrence and possible transformation into BCC cautions follow up at regular intervals.

PubMed: 25839021
DOI: 10.4103/2278-330X.149951

Review

Authors: Oscar Tellechea, José Carlos Cardoso, José Pedro Reis...

Benign follicular tumors comprise a large and heterogeneous group of neoplasms that share a common histogenesis and display morphological features resembling one or several portions of the normal hair follicle, or recapitulate part of its embryological development. Most cases present it as clinically nondescript single lesions and essentially of dermatological relevance. Occasionally, however, these lesions be multiple and represent a cutaneous marker of complex syndromes associated with an increased risk of visceral neoplasms. In this article, the authors present the microscopic structure of the normal hair follicle as a basis to understand the type and level of differentiation of the various follicular tumors. The main clinicopathological features and differential diagnosis of benign follicular tumors are then discussed, including dilated pore of Winer, pilar sheath acanthoma, trichoadenoma, trichilemmoma, infundibuloma, proliferating trichilemmal cyst/tumor, trichoblastoma and its variants, pilomatricoma, trichodiscoma/fibrofolliculoma, neurofollicular hamartoma and trichofolliculoma. In addition, the main syndromes presenting with multiple follicular tumors are also discussed, namely Cowden, Birt-Hogg-Dubé, Rombo and Bazex-Dupré-Christol syndromes, as well as multiple tumors of follicular infundibulum (infundibulomatosis) and multiple trichoepitheliomas. Although the diagnosis of follicular tumors relies on histological examination, we highlight the importance of their knowledge for the clinician, especially when in presence of patients with multiple lesions that may be the cutaneous marker of a cancer-prone syndrome. The dermatologist is therefore in a privileged position to recognize these lesions, which is extremely important to provide further propedeutic, appropriate referral and genetic counseling for these patients.

Topics: Acanthoma; Adenoma; Diagnosis, Differential; Female; Follicular Cyst; Hair Diseases; Hair Follicle; Humans; Male; Neoplasms, Basal Cell; Skin Neoplasms; Syndrome

PubMed: 26734858
DOI: 10.1590/abd1806-4841.20154114

Authors: Michael K Chai, Phillip Tenzel, Codrin Iacob...

Trichilemmal carcinomas are rare malignant adnexal tumors which can involve the head and, rarely, the eyelid. Accurate diagnosis and differentiation from basal cell carcinoma or trichoepithelioma are dependent on histopathological and immunohistochemical analysis. We report a case of an eyelid mass, initially diagnosed by incisional biopsy as a trichoepithelioma, later found on excisional biopsy to be a trichilemmal carcinoma and present a review of the literature of the histopathology, differential diagnosis and management. Consideration of these entities will be useful to the histopathologist and clinician to better identify and treat these challenging lesions.

PubMed: 28860920
DOI: 10.1016/j.sjopt.2017.05.002